CarbonCure’s CO2-infused process strengthens concrete

CarbonCure Technologies of Dartmouth, N.S. is looking to make concrete stronger and greener by infusing it with recycled carbon dioxide (CO2). The concept isn’t new, but CarbonCure’s process is. The company’s patented technology has been used in several recent construction projects and earned the firm industry kudos.

The CO2-infusion process doesn’t change the colour, texture or curing process: “It’s the same concrete [contractors] are used to. It’s made with the same materials. It’s just a greener product … from their perspective, they wouldn’t even know we had treated it with CO2,” says Jennifer Wagner, vice-president of sustainability at CarbonCure Technologies.

The technology works like this: concrete plants retrofitted with CarbonCure equipment inject liquid carbon dioxide into wet concrete as it’s being mixed. The CO2 reacts with calcium contained in cement and undergoes a chemical conversion to become a calcium carbonate mineral. Converting the carbon dioxide into mineral form prevents it from being released into the atmosphere.

This process strengthens concrete by roughly 10 to 20 per cent, depending on the mix, where it’s used and what for while reducing pollution (the production of cement accounts for about five per cent of global greenhouse gas emissions). The CO2 comes from industrial gas suppliers who collect it from smokestack emissions at coal plants, oil refineries, fertilizer plants and the like. Purified and liquefied CO2 is put into pressurized tanks then delivered to concrete plants that use CarbonCure’s technology.

Using carbon dioxide in concrete for construction purposes is not a new idea. While the science has been around for decades, “the way we do it is different,” explains Wagner.

In previous applications, CO2 was pumped into curing chambers after concrete blocks had already been produced. By contrast, “We’re introducing the CO2 much earlier, when the concrete is mixing,” explains Wagner.

Early stage CO2 infusion means the process can be applied to ready mixed concrete, she continues. CarbonCure developed a way to use the technology in ready mixed about two years ago and has focused its efforts on this lucrative segment ever since.

CarbonCure was founded a decade ago by Robert Niven, who remains CEO. Niven has an MSc from McGill University in environmental engineering and a BSc from the University of Victoria in chemistry. After launching CarbonCure, Niven and his staff spent years doing R&D.

CarbonCure licenses its technology to concrete producers, who in turn sell CO2-sequestered concrete to contractors, builders, construction firms, etc. This specialty concrete is available from about 40 producers in Canada and the U.S., says Wagner, who adds, “We’re growing pretty quickly.”

Wagner says CO2-enhanced concrete costs about the same as regular concrete. Some producers optimize the process by decreasing the amount of cement used in the mix, which can lead to cost-savings, she states.

CarbonCure has roughly two-dozen employees at two offices, in the Halifax-area and Birmingham, Ala. The latter branch was opened to accommodate rapid growth in the southern U.S. In addition to licensing its technology, CarbonCure teams manufacture and assemble CO2 equipment and install it in concrete plants.

“Our key areas of growth are major metropolitan markets across Canada and the U.S.: Toronto, Vancouver, Alberta, then in through the U.S. primarily on the eastern seaboard, from Atlanta up to Boston and then again on the west coast,” says Wagner.

Customers range from small concrete producers to multi-nationals such as Thomas Concrete. Headquartered in Sweden, Thomas Concrete tried out CarbonCure’s CO2 recycling technology at its Doraville, Ga. facility in February, 2016. The company was duly impressed and rolled the technology out to four more concrete plants in Georgia a few months later.

“By recycling CO2 in five of its Atlanta metropolitan plants, Thomas Concrete is expecting to reduce CO2 emissions by approximately five million pounds every year. This is the equivalent to taking almost 500 passenger vehicles off the road each year,” reads a June 6, 2016 press release from Thomas Concrete.

Wagner sees CarbonCure’s CO2 process as a win-win proposition: “The technology not only allows us to make greener products, it also allows us to put in stronger products. So even if there isn’t necessarily a big demand from the marketplace in terms of green, there’s still motivation for the producer to improve their products in terms of strength.”

Another motivation: CarbonCure’s technology can be used to contribute to LEED points in some cases.

To date, the CarbonCure technique has been used in “a pretty diverse” range of projects, says Wagner. These range from resorts to residences and commercial facilities.

Nova Scotia construction firm B.D. Stevens used concrete treated with CarbonCure’s CO2 process when building a new headquarters and vehicle maintenance service centre for Ambassatours Gray Line. Ambassatours is a popular Nova Scotia tour company and its 32,000-sq.-ft. head office/service centre is based in Halifax. According to Wagner, this development marked the first major construction project anywhere using CarbonCure’s CO2-infused concrete. The facility opened June 22, 2016 and has earned raves from the owners.

“There’s no issues whatsoever in terms of structure or cracks or anything … I have nothing but positive things to say about [the project] really,” states Dennis Campbell, CEO of Ambassatours Gray Line.

Using CO2-infused concrete cost “slightly more, but not a terrific amount,” he adds.

Other recent projects that have used CarbonCure’s process include the Hullmark Centre, a pair of luxury condominium towers in Toronto built by construction firm Deltera that include retail outlets and restaurants. Developer Tridel specifically requested CO2-enhanced concrete for this development. A concrete masonry wall in the Hullmark Centre parking lot was painted bright orange with a notice citing the benefits of eco-friendly concrete. (“That orange wall is storing CO2” reads a sign in the garage).

The Washington. D.C.-based MGM National Harbor resort, completed last year, is a high-profile American project that used concrete put through CarbonCure’s CO2 process. Built by contractor Whiting-Turner, the resort consists of a hotel, casino, dining, retail and entertainment facilities spread over one million square feet.

Concrete producers and contractors aren’t the only ones who have started to recognize CarbonCure’s technology.

In January, it was announced that a team led by CarbonCure were semifinalists in the $20 million NRG COSIA “Carbon XPrize”, an international competition to find ways to convert carbon dioxide into commercial products. XPrizes are awarded in various categories and sponsored by different companies. The sponsors of the Carbon XPrize are the Canadian Oil Sands Innovation Alliance (COSIA), an industry group and NRG, an American energy company. The winning team will be announced in 2020.

On March 1, CarbonCure stated that it would be receiving up to $3 million from Emissions Reduction Alberta (ERA) to enhance its technology in Alberta. ERA is a non-profit organization devoted to moving Alberta’s economy to lower carbon use.

As for the future, CarbonCure officials want to grow their firm organically across North America and eventually into Europe and Asia.

While another company could theoretically develop its own version of CarbonCure’s technology, Wagner says, “Our biggest competitor is the status quo. Concrete producers are very conservative. They are very careful when adopting new technologies and this is a new technology, so I think that’s a barrier moving forward. [We have to] continue to demonstrate that the technology has value and is proven and that will help us scale rapidly.”